U.S. Secretary of State John Kerry ended his 10-day stay at a Boston hospital on June 12 and said he will fully engage in the Iran nuclear talks at the end of the month.

Appearing in public for the first time since surgery to repair his leg broken in a cycling accident in France, Kerry sought to dispel doubts about his involvement in the negotiations.

"I will be leaving to go for the last slog on the Iran talks," Kerry said as he left Massachusetts General Hospital. "I will be absolutely, fully, and totally engaged in those talks. I am now. I haven't missed a tick."

Kerry said he plans to join the Iran talks after strategic economic talks with China in Washington June 22-24.

Kerry said he will "press forward at this critical moment in the negotiations," adding, "There's a lot of work on the table...It's a tough slog. It's not easy."